Integrated passive optical tap and optical signal termination

ABSTRACT

An integrated pluggable optical tap module configured to be coupled to a host interface of a network equipment for tapping a signal of an optical transport link comprises a first, a second optical interface, and an active optical receiver. The optical pluggable module also includes a passive optical tap for splitting a signal received from the first optical interface and transmitting the signal on the second optical interface and a copy of the signal to the active optical receiver. The active optical receiver converts said signal to an electrical signal for transmission to the host interface.

FIELD OF THE INVENTION

The present disclosure relates to optical signal transport.

BRIEF SUMMARY

An integrated pluggable optical tap module configured to be coupled to ahost interface of a network equipment for tapping a signal of an opticaltransport link comprises a first, a second optical interface, and anactive optical receiver. The optical pluggable module also includes apassive optical tap for splitting a signal received from the firstoptical interface and transmitting the signal on the second opticalinterface and a copy of the signal to the active optical receiver. Theactive optical receiver converts said signal to an electrical signal fortransmission to the host interface.

An integrated pluggable optical tap module configured to be coupled to ahost interface of a network equipment for tapping a signal of an opticaltransport link comprises a first optical interface coupled to an opticalto electrical converter and a second optical interface coupled to anelectrical to optical converter. An electrical tap is included forsplitting a signal received from the optical to electrical converter andfor transmitting the signal on the electrical to optical converter fortransmission on the second optical interface and for transmitting a copyof the signal to the host interface.

The foregoing and additional aspects and embodiments of the presentdisclosure will be apparent to those of ordinary skill in the art inview of the detailed description of various embodiments and/or aspects,which is made with reference to the drawings, a brief description ofwhich is provided next.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the disclosure will becomeapparent upon reading the following detailed description and uponreference to the drawings.

FIG. 1 is an example of an active optical tap device.

FIG. 2 is an example of a passive optical tap device.

FIG. 3 is an example of an optical fiber splitter.

FIG. 4 is an example of a first embodiment of an Integrated PluggableOptical Tap.

FIG. 5 depicts a detailed embodiment of the Integrated Pluggable OpticalTap.

FIG. 6 depicts a second detailed embodiment of the Integrated PluggableOptical Tap.

FIG. 7 depicts a second detailed embodiment of the Integrated PluggableOptical Tap.

While the present disclosure is susceptible to various modifications andalternative forms, specific embodiments or implementations have beenshown by way of example in the drawings and will be described in detailherein. It should be understood, however, that the disclosure is notintended to be limited to the particular forms disclosed. Rather, thedisclosure is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of an invention as defined by theappended claims.

DETAILED DESCRIPTION

Because of certain regulatory arrangements or security concerns or forout-of-service monetized functions, optical physical transport may betapped in order to have access to an exact copy of transmittedinformation.

The act of tapping must be transparent to the underlying networkfunctionality and thus have almost no impact on the transported signaland must not affect connectivity.

For scalability reasons, the equipment used for tapping should becost-effective, have a small foot-print and be easy to maintain whilebeing robust and reliable.

One existing solution for optical tapping is shown in FIG. 1 and knowngenerically as active optical tap device.

The active optical tap device 100 terminates the optical physicaltransport link 110 using optical transceiver 108 a. The device splitsthe signal and transmits one copy of the signal on the tapping link 112via an optical transceiver 108 b and the other copy on an intermediarylink 114 via a third optical transceiver 108 c. The intermediary link114 terminates into the network equipment 102 using another opticaltransceiver 108 d. Note that the four optical transceivers 108 a . . .108 d only use one direction (receiving or transmitting) thus half ofthe component is unused. The signal is processed by the networkequipment 102 and sent to a network 104 via another link 118. The activeoptical tap device 100 requires a power input.

The issues with using active optical tap systems are that they requirepower and they may become a single point of failure affecting the mainpath. A high density tap system may become a single point of failure formany network paths at once. Device failure, manipulation and servicingimpact the tapped transported signal. The devices require additionalspace (usually rack mounted) and lead to more inventory to manage. Extraoptical transceivers 107 a and 107 c are required to terminate theoriginal signal at the active optical tap system. An extra opticalmodule 108 b is required to terminate the tapped signal, when only thereceive path is used.

Another existing solution is the passive optical tap device as shown inFIG. 2.

The passive optical tap device 200 terminates the optical physicaltransport link 110. The passive device splits the signal and transmitsone copy of the signal on the tapping link 112 and the other copy onintermediary link 114 which terminates into the network equipment 102using another optical transceiver 106. The signal is processed by thenetwork equipment 102 and sent to a network 104 via another link 118.The passive optical tap device 200 does not require a power input.

The issues with the passive optical tap devices include the need for aseparate device which requires additional space (usually rack mounted)and inventory management. An extra optical module is required toterminate tap signal (where only the receive path is needed).Manipulation of the device may affect entire tapped links.

Another existing solution is the optical fiber splitter as shown in FIG.3. In this solution, the optical physical transport link 110 terminateson an optical connector 300 a which connects to the input of the opticalfiber splitter 302. The optical fiber splitter 302 splits the opticalsignal received and transmits one copy to the tapping link 112 viaanother optical connector 300 b. The other copy of the signal is sent tothe intermediary link 114 which terminates into the network equipment102 using another optical transceiver 106. The signal is processed bythe network equipment 102 and sent to a network 104 via another link108.

The issues with the optical fiber splitter device include fiber cablemanagement which becomes increasingly complex, especially for scaleddeployment, inventory management, and an extra optical module isrequired to terminate tap signal, when only the receive path is used.Manipulation of the device may affect the entire tapped links.

An Integrated Pluggable Optical Tap (IPOT) module is exemplified in FIG.4 as a first embodiment. The module 400 is integrated into an opticalpluggable module, such as but not limited to, Small Form-factorPluggable (SFP), C form-factor pluggable (CFP), Quad Small Form-factorPluggable (QSFP), 10 Gigabit Small Form Factor Pluggable (XFP), Enhancedsmall form-factor pluggable transceivers (SFP+) or optical pluggablemodules conforming to the XENPAK standard known in the art. The lengthof the module can adapt to the desired design requirements.

In the first embodiment, the IPOT 400 is plugged directly into thenetwork equipment 102. The optical physical transport link 110terminates a first interface 402 of the IPOT 400. The IPOT 400 splitsthe signal and transmits a copy directly to the tapping link 112, via asecond interface 404 while the other copy of the signal is processed bythe network equipment 102 and sent to a network 104 via another link108.

Referring to FIG. 5, the IPOT module 400 comprises two stages; a passiveoptical tap stage 502 and an active optical receiver stage 504.

The passive optical tap stage 502 has no active component. It provides aconnection point 550 a and 550 b for the link 110 requiring a tap andfor the tapping link 112 and houses the signal splitter 510 whichcreates a copy of the incoming optical signal 505 and transmits theoriginal signal to the connector 550 b and the tapping link 112.

The active optical transceiver stage 504 is an active component 506 thatreceives an optical signal 515 and converts it to an electrical signal517. Only the required receiving function is implemented unlike priorart solutions, therefore there are no wasted functionality in thecomponent, leading to lower consumption is minimized since only thereceiver path is required. The electrical signal is then passed to thehost interface 508 for transmission to the network equipment andprocessing by the network equipment.

The IPOT module can optionally be designed such that the passive opticaltap stage can be disconnected at 560 from the package formaintainability, with no interruption to tapped link communication.

The signal splitter technologies are known in the art and may comprisebut are not limited to one of dielectric mirrors, beam splitter cubes(prisms), fuse biconical taper (fiber couplers), planar lightwavecircuit. The choice of the technology depends on cost, size, power andhow much degradation can be accounted for by the optical to electricalconverter.

The IPOT can be designed to support any optical slip ratios, any typesof wavelengths, any types of connectors, any types of fiber (e.g.single-mode and multi-mode fiber, etc. . . . ) and any link speeds.

This embodiment provides several advantages over existing solutions,comprising: savings in component cost since there is no need for anextra SFP to terminate tap signal and no need of a patch fiber. Reducedinventory management and no wasted transmitter which optimizes powerusage. The solution is very scalable as the cost of the tapping solutionis proportional to links requiring a tap. The usefulness of thepassively tapped signal is maximized since the receiver electronicsfeeds directly off the tapped signal. The electronic transceiver stageis decoupled from the passive optical stage allowing for maintenance ofthe transceiver without interruption to tapped link. There is no lasersafety hazard certification required since the package only acts as areceive path, thus no laser generation, making the design process lessdemanding, making it safer for the craft-person to plugging in themodule in a host device.

Referring to FIG. 6, the active optical transceiver stage 504 mayoptionally include a smart function component 606. Programmable logiccan be embedded in the component 606 of the device in order to providevalue added, on demand, customized and dynamic functionality toevaluate, monitor and/or modify the signal. Example of value addfunctionality include any combination, but not limited to, one or moreof the following: Rate conversion from 10 Gbps (Tap side) to 1 Gbps(Host side), rate conversion from 1 Gbps (Tap side) to 100 Mbps (Hostside), packet filtering, traffic policing and traffic shaping,performance monitoring, statistics gathering and network synchronizedtime-stamping of captured frame. In this embodiment, the IPOT module canalso optionally be designed such that the passive optical tap stage canbe disconnected at 560 from the package for maintainability, with nointerruption to tapped link communication.

Now referring to FIG. 7, if the passive aspect of the tapping is notimportant to ensure reliability of the part, an embodiment of the IPOT400 can combine an active tap and termination, where the tap action isdone on the electrical side of the signal termination. In this case theincoming optical signal 110 is sent to an optical to electricalconverter 702, the resulting electrical signal 710 is processed by thesmart function component 706 which may evaluate, monitor and/or modifythe signal before sending the signal 712 to the host interface 508. Thesmart function 706 also performs the splitting of the signal andtransmits a copy 716 of the electrical signal to the tapping link 112via an electrical to optical converter 704.

This embodiment maintains all the unique aspects of the invention(except for the advantage of maintainability and resiliency of thepassive stage) and also supports all the enumerated variations mentionedabove.

One of the many benefits of integrating the value add functionalitieslisted above is to have a significant resource saving impact (capitaland operating expenses) on the system deployment requirements byreducing the demand on the network equipment and infrastructure neededto interface with the network

Although the algorithms described above including those with referenceto the foregoing flow charts have been described separately, it shouldbe understood that any two or more of the algorithms disclosed hereincan be combined in any combination. Any of the methods, algorithms,implementations, or procedures described herein can includemachine-readable instructions for execution by: (a) a processor, (b) acontroller, and/or (c) any other suitable processing device. Anyalgorithm, software, or method disclosed herein can be embodied insoftware stored on a non-transitory tangible medium such as, forexample, a flash memory, a CD-ROM, a floppy disk, a hard drive, adigital versatile disk (DVD), or other memory devices, but persons ofordinary skill in the art will readily appreciate that the entirealgorithm and/or parts thereof could alternatively be executed by adevice other than a controller and/or embodied in firmware or dedicatedhardware in a well known manner (e.g., it may be implemented by anapplication specific integrated circuit (ASIC), a programmable logicdevice (PLD), a field programmable logic device (FPLD), discrete logic,etc.). Also, some or all of the machine-readable instructionsrepresented in any flowchart depicted herein can be implemented manuallyas opposed to automatically by a controller, processor, or similarcomputing device or machine. Further, although specific algorithms aredescribed with reference to flowcharts depicted herein, persons ofordinary skill in the art will readily appreciate that many othermethods of implementing the example machine readable instructions mayalternatively be used. For example, the order of execution of the blocksmay be changed, and/or some of the blocks described may be changed,eliminated, or combined.

It should be noted that the algorithms illustrated and discussed hereinas having various modules which perform particular functions andinteract with one another. It should be understood that these modulesare merely segregated based on their function for the sake ofdescription and represent computer hardware and/or executable softwarecode which is stored on a computer-readable medium for execution onappropriate computing hardware. The various functions of the differentmodules and units can be combined or segregated as hardware and/orsoftware stored on a non-transitory computer-readable medium as above asmodules in any manner, and can be used separately or in combination.

While particular implementations and applications of the presentdisclosure have been illustrated and described, it is to be understoodthat the present disclosure is not limited to the precise constructionand compositions disclosed herein and that various modifications,changes, and variations can be apparent from the foregoing descriptionswithout departing from the spirit and scope of an invention as definedin the appended claims.

What is claimed is:
 1. A pluggable optical module configured to beintegrated to a host interface of a network equipment for tapping asignal of an optical transport link comprising: a housing compatiblewith a pluggable transceiver module of the network equipment, thepluggable optical module disposed within the housing; a first opticalinterface; a second optical interface; a passive optical tap creating acopy of an optical signal received from the first optical interface andtransmitting the optical signal on the second optical interface, thepassive optical tap transmitting the copy of the optical signal to anactive optical receiver; the active optical receiver converting the copyof the optical signal to an electrical signal; the host interfacecoupled to the active optical receiver, the host interface receiving theconverted electrical signal, wherein the passive optical tap transmitsthe copy of the optical signal within the housing to the active opticaltap via a free space transmission path; and wherein the passive opticaltap can be disconnected from the pluggable optical module with nointerruption to a tapped link communication.
 2. The pluggable opticalmodule of claim 1 wherein the pluggable optical module is selected fromthe group consisting of SFP, SFP+, CFP, QSFP, XFP, XENPAK.
 3. Thepluggable optical module of claim 1 wherein creating a copy is achievedby a technology selected from a group of dielectric mirrors, beamsplitter cubes, fuse biconical taper, planar lightwave circuit.
 4. Thepluggable optical module of claim 1 further comprising a smart functionmodule to modify the electrical signal before sending to the hostinterface.
 5. The pluggable optical module of claim 4 wherein the smartfunction comprises one or more of rate conversion, packet filtering,traffic policing, traffic shaping, performance monitoring, performancestatistics gathering, network synchronized time-stamping of capturedframe.